Ceiling grid system



Jan. 28, 1964 G. C.'ADAMS CEILING GRID SYSTEM 3 Sheets-Sheet 1 Filed Dec. 14, 1961 A5? /A? M4 BY w United States Patent 3,119,475 CEILING GRID SYSTEM George C. Adams, Ann Arbor, Micln, assignor to Rollform, Incorporated, Ann Arbor, Mich, a corporation of Michigan Filed Dec. 14, 1961, Ser. No. 159,410 Claims. (Cl. 18982) This invention relates generally to acoustical ceilings and more particularly to a grid system for an acoustical ceiling that maintains its integrity upon the occurrence of a relatively high ambient temperature condition.

This is a continuation-in-part application of copending application, Serial No. 93,735, filed March 6, 1961, now abandoned, for: Ceiling Grid System.

Acoustical ceilings are often suspended from the conventional ceiling or overhead structure of an enclosure to provide an aesthetically pleasing and acoustically superior ceiling for the enclosure. Such acoustical ceilings are generally made up of a plurality of acoustical panels that are supported by a rigid grid system comprising a plurality of interlocking elongated grid members arranged in generally normal relation to one another. Such a grid system is disclosed in application Serial No. 772,042 assigned to the assignee of the present invention.

Because the acoustical panels are supported by the interlocking grid members, any buckling of the grid system may tilt or dislodge the acoustical panels from the supporting grid members, creating gaps in the acoustical ceiling. Buckling of the grid system often occurs due to longitudinal expansion of the grid members upon the occurrence of relatively high ambient temperatures due to, for example, a fire in the space underlying the acoustical ceiling, which thereupon exposes the conventional ceiling or overhead structure of the enclosure to the conflagration in the underlying space.

Accordingly, certain specifications and fire regulations have been formulated that require that the integrity of the acoustical ceiling be maintained despite the relatively high temperature condition occasioned by a fire in the underlying space. Thus, acoustical ceilings are required to be, in effect, fire barriers between the floor area or underlying space and the conventional ceiling of the room.

The acoustical ceiling of the present invention offers a solution to the problem of buckling of the grid system by accommodating longitudinal expansion of the grid members due to a relatively high temperature condition. Provision is made for longitudinal expansion of the grid members with respect to one another without disrupting the spacing between parallel ones of the grid members. Therefore, buckling of the grid system, with its inherent displacement of the acoustical panels, is precluded.

In accordance with one embodiment of the present invention, longitudinal expansion of the grid members is accommodated by a plurality of fusible shear links that normally rigidly maintain the spaced relationship between respective ones of the grid members but which, upon the occurrence of heat-induced expansion, shear or fuse to permit the grid members to move toward one another thereby to accommodate longitudinal expansion. The fusible shear links are easily engageable with the grid members making up the grid system, thereby to provide a ceiling construction that is relatively inexpensive and easy to install, yet maintains its integrity under relatively high ambient temperature conditions.

In accordance with another embodiment of the present invention, longitudinal expansion of the grid members is accommodated by a novel resilient finger.

Novel cover plates underlie the junction of the grid members in a manner that renders the junction aesthetically pleasing and insures the structural integrity of the grid system upon expansion.

Patented Jan. 28, 1964 Accordingly, one object of the present invention is an improved acoustical ceiling construction.

Another object is an acoustical ceiling construction that provides a positive fire barrier between the floor and ceiling of a room.

Another object is an acoustical ceiling construction that accommodates longitudinal expansion of the grid members of an acoustical ceiling grid system.

Another object is a supporting grid for acoustical panels that maintains its structural integrity under relatively high ambient temperature conditions.

Another object is an acoustical ceiling construction that includes a fusible shear link that permits expansion and relative movement of the members forming the supporting grid system for the acoustical panels without varying the relative spacing therebetween.

Another object is an improved cover plate for the junction of the grid members of an acoustical ceiling.

Another object is a cover plate having close-fitting side flanges that strengthen the entire grid structure of an acoustical ceiling.

Another object is a cover plate having side flanges that overlap and conceal the side edges of the grid members at the junction thereof.

Another object is a cover plate that protects joints between the grid members of an acoustical ceiling against fire.

Another object is a cover plate that holds the cross grid members on opposite sides of a main grid member exactly in alignment with each other and thus contributes to the speed with which the ceiling grid system can be assembled.

Another object is a grid system for an acoustical ceiling that is retained in a rigid condition by resilient fingers on splicer elements.

Other objects and advantages of the present invention will be apparent in the following specification, claims and drawings, wherein:

FIGURE 1 is a fragmentary perspective view of a grid system for the support of the acoustical panels of an acoustical ceiling;

FIG. 2 is a fragmentary perspective view of the juncture of a pair of cross grid members with a main grid member;

FIG. 3 is a cross-sectional view taken substantially alon the line 33 of FIG. 2;

FIG. 4 is a cross-sectional view taken substantially along the line 4-4 of FIG. 3;

FIG. 5 is a cross-sectional view taken substantially along the line 5-5 of FIG. 3;

FIG. 6 is a cross-sectional View taken substantially along the line 66 of FIG. 2;

FIG. 7 is a view taken substantially in the direction of the arrow 7 of FIG. 2;

FIG. 8 is a perspective view of the fusible shear link;

FIG. 9 is a fragmentary perspective view of the cover plate for the junction of the grid members;

FIG. 10 is a view of a junction between modified main and splicer members;

FIG. 1'1 is a view in the direction of the arrow 11 in FIG. 10;

FIG. 12 is a view taken substantially along the line 1212 of FIG. 10, and enlarged for clarity;

FIG. 13 is a side elevational view of a modified fusible element; and

FIG. 14 is a cross-sectional view taken substantially along the line 1414 of FIG. 13.

Referring to FIGS. 1 and 2 of the drawings, a grid system 10, for an acoustical ceiling, comprises a plurality of parallel spaced-apart main grid members 12, of generally inverted T-shaped vertical cross section defined by a vertical flange 14 and horizontal flanges 18 and 20.

Aligned ones of the main grid members 12 are joined by expansion 'splicers 22, as will be more particularly described hereinafter.

A plurality of cross grid members 34 having a generally inverted T-shaped vertical cross section defined by a verticalflange 32 and horizontal flanges 34 and 36, extend transversely between spaced ones of the main grid members 12. The cross grid members 36 may also extend transversely between spaced ones of the cross grid members halfway between and parallel to the main grid members 12 thereby to orientate the grid system 16 into an aesthetically pleasing pattern comprising a plurality of generally rectangular spaces for the acceptance of conventional rectangular acoustical panels 40.

As best seen in FIG. 2, the acoustical panels are supported on the horizontal flanges 18 and 20 of the main grid members 12 and on the flanges 34 and 36 of the cross grid members 30. The panels 46 normally are restrained against excessive horizontal movement by the vertical flanges 14 and 32 of the grid members 12 and 3t), respectively.

The entire grid system 10 may be supported from a ceiling or other suitable structure (not shown), by a plurality of wire hangers 59, the lower ends of which are attached to the vertical flanges 14 of the main grid members 12.

As best seen in FIG. 3, the adjacent ends and 62 of aligned cross grid members 30 have longitudinally extending tabs 64 and 66 that project longitudinally from the upper and lower halves, respectively, of the vertical flanges 32. Thus, each cross member 30 has a tab 64 extending from the upper half of the vertical flange 32 at one end 60 thereof, and a tab 66 extending from the lower portion of the vertical flange 32 at the opposite end 62 thereof.

The main grid member 12 has a plurality of spaced pairs of vertically orientated slots 70 and 72 therein (FIG. 2) for the acceptance of the tabs 64 and 66, respectively, on the cross grid members 30. As is more particularly described in application Serial No. 772,042, the tabs 64 and 66 are provided with longitudinally extending slots and 82, respectively, for the acceptance of a pair of resilient locking pins 34 and 86, respectively, on opposite sides of the vertical flange 14 of the main grid member 12, thereby to position and resiliently lock the tabs '64 and 66 against retraction out of the slots 79 and 72.

In accordance with the present invention, shear links are inserted into the slots 80 and 82 on the opposite side of the vertical flange 14 and opposite the pins 84 and 86, respectively so that the flange 14 is confined in each instance between a shear link and a pin. It is contemplated that the shear links 90 be made from any material that melts or otherwise disintegrates under fire conditions in use. In the case of fusible shear links, the material from which the links are formed should preferably melt within the range 225325 F. Many plastic resin materials are satisfactory for this purpose, and polyethylene is a typical example of such a material.

As best seen in FIG. 4, the shear links 90 are of T -shaped vertical cross section defined by a vertical portion 92 and a horizontal portion 94, the portion 94 having a locking shoulder 95 thereon that is engageable with the area adjacent the slot accepting the link 90.

Thus, the tabs' 64 and 66 are locked against movement within the complementary slots 70 and 72 in the vertical flange 140i the main grid member 12 by the fusible shear links 90 and by the resilient'pins 84 and 86, respectively. In oth r words, fusible shear links 91) normally define rigid stops that dictate the limit of movement of the tabs 64 and 66 through the slots 70 and 72, respectively, the tabs 64 and 66 being positively lockable within the slots 76 and 72 by the resilient pins 84 and 86 in the slots 80 and 82 on the opposite side of the flange 14. It is to be noted that the flanges 34 and 36 of the cross grid members 30 are relieved by cutouts '76 and 78 to provide for subsequent movement of the cross grid members 30 toward the main grid member 12, as will be described.

Upon the occurence of a predetermined temperature condition, the fusible shear links 90 soften and melt, thereby to accommodate longitudinal expansion of the cross grid members 30 by permitting movement of the tabs 64 and 66 through the slots 70 and 72 in the flange 14 of the main grid member 12. Thus, longitudinal expansion of the cross grid members 30 is accommodated without varying the spacing between the main grid members 12 or causing the grid system 10 to buckel.

As best seen in FIG. 6 and 7, longitudinal expansion of the main grid members 12 is accommodated by the splicer member 22. The splicer 22 has a dished center portion in alignment with the vertical flange 14 of the main grid members 12. The dished portion 100 has a pair of slots 192 and 104 therein for the acceptance of the tabs 64 and 66 on the end portions 60 and 62 of the cross grid members 30. The tabs 64 and 66 are retained within the slots 102 and 104 in a manner similar to their retention within corresponding slots 70 and 72 in the flange 14 of the main grid members 12, described hereinbefore.

The splicer element 22 has a plurality of horizontally extending foldable tabs 110, 111 and 112 at one end 113 thereof and a like plurality of foldable tabs 114, 115 and 116 at the other end 117 thereof that are accepted in complementary slots 12%, 121 and 122 in the opposite end portions of the main grid members 12. Upon insertion of, for example, the tabs 110, 111 and 112 through the slots 120, 121 and 122, respectively, end portions 124, 125 and 126 of the tabs 110, 111 and 112 are folded to a vertical position, as by gripping the end portions 124, 125 and 126 with the jaws of a pliers and twisting thereby to preclude lateral disassociation of the splicer element 22 from the main grid member 12.

As best seen in FIGS. 6 and 7, relative longitudinal movement between the splicer 22 and main grid members 1 2 is normally precluded by fusibie shear links 90 that are inserted through complementary slots 130 and 132 in the splicer 22. Thus, upon assembly of the entire grid system 10, relative longitudinal movement between the splicer members 22 and grid members 12 is precluded until such time as the fusible elements 90 are heated sufflcien-tly to effect shearing or melting thereof. Such relative longitudinal movement of the grid sections 12 toward one another is guided by the tabs 110, 111 and 112 in the slots 120, 121, and 122, respectively, and by a cover plate In accordance with another feature of the present invention and as best seen in FIGS. 3 and 5, the junction of the cross grid members 30 with the main grid member 12 is enclosed from the bottom by the cover plate 150. The cover plate 150 has four normally orientated leg pontions 152, 154, 156 and 158. As best seen in FIG. 9, the leg portions 152, 154, 156 and 158 have opposite edge flanges 160-162, 164-166, 168170, and 172 174, respectively, that extend upwardly to receive and guide the flange portions 1 820 and 3436 of the main and cross grid members 12 and 30, respectively. Suitable foldable tabs retain the plate 150 in juxtaposed but slidablle relation with the grid members 12 and 30. Thus, the flanges 160 through 174 on the plate 150 maintain the cross members '30 and main grid members 12 in normal relationship despite relative longitudinal expansion and movement thereof, even after the fusible links 90 have sheared or melted. In this manner, the plate 150 gives the grid system 10 an aesthetically pleasing appearance from the floor area underlying the acoustical ceiling, yet retains the members 12 :and 30 upon relative movement thereof with respect to one another and with respect to the cover plate 150.

In a modified embodiment of the present invention, shown in FIGS. 10, 11 and 12, longitudinal expansion of a main grid member 220 is accommodated by a splicer member 222. The splicer 222 has a dished center portion 224 in alignment with :a vertical flange 226 of the main grid member 220. The dished portion 224 of the splicer 222 "has a pair of slots 228 and 230' therein for the acceptance of complementary tabs 64 and 66 on the end por tions 60 and 62 of the cross grid members 30. The tabs 64 and 66 are retained within the slots 228 and 230 in a manner similar to their retention within corresponding slots 70 and 72 in the flange 14 of the main grid members 12, as described hereinbefore.

The splicer element 222 has a plurality of horizontally extending foldable tabs 240, 242 and 244 at one end 246 thereof and a like plurality of foldable tabs 248, 250 and 252 at the other end 254 thereof that are accepted in complementary slots 260', 262, and 264 in the opposite end portions of the main grid members 226, one of which is shown. Upon insertion of, for example, the tabs 248, 250 and 252 through the slots 260, 262 and 264, respectively, end portions 266, 268 and 270 of the tabs 248, 250 and 252 are folded to a vertical position, as by twisting with a pliers, to preclude lateral disassociation of the splicer element 222 from the main grid member 220.

As best seen in FIGS. 10, 11 and 12, relative longitudinal movement between the splicer 222 and main grid member 220 is normally precluded by a finger 280 having an end portion 282 that extends through the complementary slot 264 in the grid member 220. Thus, after assembly of the grid system, relative longitudinal movement between the splicer member 222 and grid member 220 is precluded until such time as relative longitudinal movement of the grid sections 220 toward one another flexes the finger 280.

In accordance with yet another embodiment of the present invention, as best seen in FIG. 13, a modified fusible shear element 300' is of C-shaped vertical crosssection so as to be acceptable on a complementary end portion 302 of a grid member 304. The end portion 302 has upper and lower shoulders 306 and 308 that normally position the fusible shear element 306 with respect to an aperture 310. Upon insertion of the end portion 302 of the grid member 304 through, for example, a slot 70 in the main grid member 12, the pin 84 is driven through the aperture 310' to lock the grid member 12 against the shear element 30-).

Upon the occurrence of a relatively high ambient temperature condition, the shear element 300* melts or shears, permitting movement of the grid member 304 toward the grid member 12, as discussed hereinbefore. Thus, the fusible element 300 is similar in function to the element 90, since it normally maintains the spaced relationship between the main and cross grid members but allows relative movement therebetween upon the occurrence of a high ambient temperature condition.

From the foregoing description, it should be apparent that the ceiling grid system of the present invention features main and cross grid members that are spaced apart at the ends and normally retained in this position. The means for normally retaining the spaced relationship of the end portion of the grid members permits release there of upon the occurrence of an ambient temperature condition sufficiently high to cause substantial longitudinal expansion of the grid members.

The spaced ends at the intersections of the grid members are closed by a cover plate of novel construction. The cover plate has upturned flanges which embrace the bottom edges of the main and cross grid members. The tabs on the flanges are adapted to be bent over the bottom flanges of the grid members to fasten the cover plate to the grid members. The cover plate is in the form of a cross where there are cross g'nid members on each side of the main grid member, as is the case in the middle of the ceiling, or it can be in the form of a T for use where there is only one cross grid member at one side of the main grid member as in certain pattern arrangements in the middle of the ceiling and at the edge of the ceiling.

The edge flanges of the cover plate extend around a radius between the arms thereof to strengthen and thicken the same, although the plate itself may be made of relatively thin metal. The plate is the same color as the bottoms of the frame members so that the exposed edges of the cover plate make a barely discernible line on the grid members. The cover plate holds the main grid members and the cross grid members exactly perpendicular to each other. This relationship is maintained because the side flanges of the cover plate lit the bottom flanges of the grid members relatively snugly and they therefore guide and control the location and position of the grid members. The cover plates, of course, cover the exposed and open joints between the frame members.

It is to be understood that the specific constructions of the improved ceiling grid system herein disclosed and described are presented for the purpose of explanation and illustration and are not intended to indicate limits of the invention, the scope oi which is defined by the following claims.

What is claimed is:

l. A grid system for an acoustical ceiling comprising a plurality of main grid members, a plurality of cross grid members, said main grid members having spaced apertures therethrough, said cross grid members extending generally normally with respect to said main grid members and having portions projecting longitudinally therefrom through the apertures in said main grid members, respectively, locking mean extending through the projecting portions on said cross grid members, respectively, on the opposite side of sm'd main grid members from said cross grid members to prevent relative movement of said main and cross grid members away from one another, and a plurality of fusible shear links extending through said cross grid members and engageable with said main grid members on the opposite side thereof (from said looking means, respectively, said shear links normally limiting relative movement of said cross grid members toward said main grid members, said fusible shear linl s accommodating longitudinal expansion of said cross grid mernlbers upon the occurrence of a predetermined temperature condition by permitting relative movement of said cross grid members toward said main grid members, respectively.

2. In a ceiling grid system, a main grid member having a vertical web portion with a slot therein, a cross grid member'extending substantially perpendicularly of said main grid member, said cross grid member having a longitudinal tab extending through said slot, a flexible and resilient tension member extending transversely through the tab on the opposite side of said main grid member from said cross grid member to draw the cross grid member toward said main grid memlber under normal conditions, and a fusible shear element extending through said cross grid on the opposite side of said main grid member from said tension member to normally restrain movement of said cross grid member toward said main grid member.

3. In a ceiling grid system, a main frame member including a laterally extending base portion and a vertical web portion having slot means therein, a pair of cross frame members at opposite sides of and extending substantially perpendicularly to said main frame member, said cross frame members including horizontal base portions and vertical web portions having longitudinal tabs extend-ing in opposite directions through said slot means, fusible shear elements associated with said cross frame members butting against said main frame member at opposite sides thereof, means for normally drawing said cross members and shear links toward said main frame member, and a cover plate having normally orientated leg portions with upstanding flanges along opposite edge portions thereof, respectively, said flange portions engaging the base portions of said main and cross grid members to maintain said main and cross members in normal orientation upon relative movement of said cross grid member towardsaid main grid member upon fusion of said shear element.

4. In a ceiling grid system, a main grid member having a vertical Web portion with aslot therein, a cross grid memberextending substantially perpendicularly of said main grid member, said cross grid member having a longitudinal ta b extending through said slot, a flexible and resilient tension member extending transversely through the tab on the opposite side of said main grid member from said cross grid member to draw the cross grid member toward said main grid member under normal conditions, and heat responsive means on the opposite side of said main grid member from said tension member for normally restraining movement of said cross grid member toward said main grid member but permitting movement of said cross grid member toward said main grid member upon the occurrenoe of a relatively high temperature condition.

5. In a ceiling grid system, a main frame member including a Web portion having slot means therein, a cross frame member extending substantially perpendicularlyto said main rfirame member, said cross frame member having a longitudinal tab extending through said slot means, the improvement comprising a generally 'C- sha ped fusible shear element disposed about the tab on said cross frame member butting against said main frame member, and means :for normally drawing said cross member and shear element toward said main frame member, said shear element providing for movement of said cross grid member toward said main grid member upon fusion thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,079,862 Kinnear NOV. 25, 1913 2,148,310 Tarlen Feb. 21, 1939 2,540,603 Urbain Feb. 6, 1951 2,829,743 Strauss et a1 Apr. 8, 1958 2,909,957 Rapata Oct. 27, 1959 3,013,644 Smith et a1 Dec. 19, 1961 

1. A GRID SYSTEM FOR AN ACOUSTICAL CEILING COMPRISING A PLURALITY OF MAIN GRID MEMBERS, A PLURALITY OF CROSS GRID MEMBERS, SAID MAIN GRID MEMBERS HAVING SPACED APERTURES THERETHROUGH, SAID CROSS GRID MEMBERS EXTENDING GENERALLY NORMALLY WITH RESPECT TO SAID MAIN GRID MEMBERS AND HAVING PORTIONS PROJECTING LONGITUDINALLY THEREFROM THROUGH THE APERTURES IN SAID MAIN GRID MEMBERS, RESPECTIVELY, LOCKING MEANS EXTENDING THROUGH THE PROJECTING PORTIONS ON SAID CROSS GRID MEMBERS, RESPECTIVELY, ON THE OPPOSITE SIDE OF SAID MAIN GRID MEMBERS FROM SAID CROSS GRID MEMBERS TO PREVENT RELATIVE MOVEMENT OF SAID MAIN AND CROSS GRID MEMBERS AWAY FROM ONE ANOTHER, AND A PLURALITY OF FUSIBLE SHEAR LINKS EXTENDING THROUGH SAID CROSS GRID MEMBERS AND ENGAGEABLE WITH SAID MAIN GRID MEMBERS ON THE OPPOSITE SIDE THEREOF FROM SAID LOCKING MEANS, RESPECTIVELY, SAID SHEAR LINKS NORMALLY LIMITING RELATIVE MOVEMENT OF SAID CROSS GRID MEMBERS TOWARD SAID 